Oilfield operating companies seek to maximize the profitability of their reservoirs. Typically, this goal can be stated in terms of maximizing the percentage of extracted hydrocarbons subject to certain cost constraints. A number of recovery techniques have been developed for improving hydrocarbon extraction. For example, many companies employ flooding techniques, injecting a gas or a fluid into a reservoir to displace the hydrocarbons and sweep them to a producing well. As another example, some heavy hydrocarbons are most effectively produced using a steam-assisted gravity drainage technique, where steam is employed to reduce the hydrocarbons' viscosity.
Such recovery techniques create a fluid front between the injected fluid and the fluid being displaced. The position of the fluid front is a key parameter for the control and optimization of these recovery techniques, yet it is usually difficult to track due to the absence of suitably feasible and effective monitoring systems and methods. Where the use of seismic surveys, monitoring wells and/or wireline logging tools is infeasible, operators may be forced to rely on computer simulations to estimate the position of the fluid front, with commensurately large uncertainties. Yet suboptimal operations may cause premature breakthrough where one part of the fluid front reaches the producing well before the rest of the front has properly swept the reservoir volume. Such premature breakthrough creates a low-resistance path for the injected fluid to follow and deprives the rest of the system of the power it needs to function. Prevention of premature breakthrough is generally considered preventable with adequate forewarning of a fluid front's approach to the producing well(s).
It should be understood, however, that the specific embodiments given in the drawings and detailed description thereto do not limit the disclosure. On the contrary, they provide the foundation for one of ordinary skill to discern the alternative forms, equivalents, and modifications that are encompassed together with one or more of the given embodiments in the scope of the appended claims.